While fad diets continue to evolve, today’s most popular diets often involve cutting out or significantly reducing carbohydrate intake. However, research suggests that the type and timing of carbohydrates consumed may be more important than total carbohydrate intake. This is where carb cycling comes in.
Carb cycling is a relatively new approach to dieting that involves alternating between high- and low-carb days. It has shown signs of being effective at improving metabolic flexibility (1), which is the body’s ability to switch between burning carbs and fat for fuel. This has been linked to a number of health benefits for women, including improvements in body composition, metabolic health, and athletic performance.
In this article, we will take a closer look at carb cycling and how it can benefit women in achieving their health goals
Carb cycling is a dietary strategy that alternates between high-carb and low-carb days. Instead of sticking to a consistent carb intake, this technique should be adjusted according to the body's metabolic processes, workout routines and goals, syncing with how our bodies naturally function.
High-carb days provide fuel for your workouts and help you replenish your glycogen stores during recovery while low-carb days allow your body to start utilizing fat as fuel. Alternating between the two can help your body become more efficient at metabolizing both of these nutrients.
Your carb cycling schedule will vary from others as it depends on many factors including your goals, current body composition, exercise routine, and more. With a personalized nutrition plan, you can learn when your body needs a low-, medium, or high-carb day to support your metabolic function better.
By regularly transitioning between periods of lower and higher carbohydrate intake, carb cycling can help the body become more efficient at metabolizing both carbs and fats.
But remember, not any carb will do. We encourage you to emphasize complex carbohydrate sources during most of your meals and snacks on high-carb days, including fruits, vegetables, whole grains, beans, and legumes. Not only are these foods rich in essential vitamins and minerals, but they are also good sources of fiber (key for hormonal balance), keeping you feeling fuller for longer, which can promote satiety during meals.
Other dieting techniques, such as very low-carb or high-carb diets, can have negative effects on your hormone levels. When eliminating carbs and fiber from your diet, you may cause drastic spikes of cortisol, “the stress hormone”. These spikes can impact on your metabolism and overall health.
Carbs are your body’s main fuel source. When you consume more than you need, depending on your age and activity level, such as with a high-carb diet, your body stores the excess carbs to be used later as glycogen in your liver.
Excessive carbohydrate intake can result in increased fat storage and insulin resistance. Over time these impacts can cause weight gain, metabolic abnormalities, and an increased risk for certain chronic diseases such as type 2 diabetes and heart disease (2).
Alternatively, following a very low-carb diet, such as keto, is often not sustainable, and long-term use can also lead to nutrient deficiencies and an increased risk for complications including heart arrhythmias, osteoporosis, kidney damage, and increased cancer risk (3).
By including a moderate amount of carbohydrates on specific days, you are stimulating enzymes that enhance the absorption and conversion of the glycogen into energy. Once these stores run out, your body has to start relying on other forms of fuel, such as fats. This improves your metabolic flexibility. Carb cycling is a great way to ensure your carbohydrate intake is optimal.
The concept behind alternating high-carb and low-carb days with carb cycling is to suit your body's needs. For example, on days when you are performing intense physical activity, your body requires glucose for fuel. Once you use up all the glucose from your bloodstream, your body taps into its glycogen stores for continued energy.
Overall, women need to tailor their carbohydrate intake to their individual needs. By gaining a deeper understanding of your body's responses to carbohydrates at different times, you can tailor your nutrition to serve your health and fitness objectives best. This includes considering hormone levels, menstrual cycle, body composition, and physical activity levels.
For those who integrate exercise into their daily life, having adequate glycogen stores helps to boost performance and endurance during exercise. As mentioned, carbs also play an essential role in maintaining an optimal level of glycogen stores. During exercise, your body breaks down glycogen into glucose so that it can use the glucose to fuel your muscles. This helps you work out at your peak performance and maintain your blood sugar levels at a normal range. Following exercise, consuming a higher-carb diet can help to replenish these glycogen stores, which can help with improving recovery time (4, 5).
Meanwhile, consuming a lower-carb diet during non-exercise days can help to shift your body into fat-burning versus fat-storing. Because you are not as active, your body does not require the same amount of glucose from carbohydrates as it does on active days. Eating a high-carb diet on these days can result in increased fat storage from unused fuel.
As women age, their muscle mass begins to decline, which can also lead to a less efficient metabolism. When your metabolism is inflexible, your body tends to burn fewer calories at rest, making it harder to lose weight. This can stem from many factors, including your lifestyle choices, activity levels, diet, health conditions, genetics and hormones. Changes in hormones throughout the monthly cycle, peri-menopause and menopause can also affect your muscle mass.
Here are some additional things to keep in mind:
Carb cycling can be particularly helpful for women trying to build lean body mass and avoid excess body weight. This is because carb cycling can help to balance insulin levels and appetite-regulating hormones (6, 7).
Eating too many carbs all the time might make you gain weight, while eating too few can be tough to stick with. Carb cycling is like a middle ground - it can help you get the results you want while you still get to enjoy your favorite carb treats now and then.
While the hormonal benefits of carb cycling are often highlighted, especially in the context of women's health, there are several other reasons why women might consider trying this dietary approach. Here are a few:
One of the main advantages of carb cycling for women is the promotion of metabolic flexibility – the ability of the body to switch between glucose and fat as primary energy sources, depending on dietary intake and energy demand (8). Metabolic flexibility is a hallmark of good metabolic health, and can potentially lower the risk for diseases like metabolic syndrome, type 2 diabetes, and cardiovascular disease.
Carb cycling can optimize energy for high-intensity or endurance workouts by ensuring adequate glycogen stores on higher-carb days. This can lead to improved performance, increased muscle mass, and decreased fatigue, which can benefit active women or those involved in regular or competitive sports.
Carb cycling can aid in weight loss and maintenance by alternating between periods of lower calorie intake (low-carb days) and higher calorie intake (high-carb days). This strategy can enhance fat loss while still allowing for metabolic recovery and prevention of metabolic adaptation, the process where weight loss slows and eventually plateaus in response to sustained caloric restriction.
By periodically lowering carbohydrate intake, carb cycling can help improve insulin sensitivity. Lower insulin levels on low-carb days allow the body to more efficiently use stored fat as fuel, which can be beneficial in managing or preventing insulin resistance, a precursor to type 2 diabetes (9).
Many people report increased mental clarity and consistent energy levels on lower-carb diets due to the reduction in blood sugar spikes and crashes. By including strategic high-carb days, carb cycling can provide these benefits while also preventing the side effects some people experience with continuous low-carb diets, such as brain fog or decreased mood (10).
While these potential benefits are promising, it's important to note that individual responses to diets can vary greatly and what works well for one person might not work for another. Using Lumen’s personalized nutrition will build a nutritional plan designed specifically for your body and individual needs.
For women interested in carb cycling, it may feel overwhelming to know where to start. First, it’s important to note that it’s not all about diet. While your nutrition plays a pivotal role, your activity, sleep, and mental health are also essential components for optimal metabolic functioning.
Use a metabolic health tracker
To help you start out, consider using a metabolic tracker to count your macros. You can also track your exercise, steps, sleep routine, and mindfulness practices to help you develop long-term habits. Many studies have found that tracking can help you become more successful.
For example, one study found that those who wore a tracking device to count their steps averaged 318 more steps per day than those who did not (11).
Another study found that those who tracked their food intake resulted in significant weight loss compared to those who did not (12).
Follow a personalized nutrition plan
With the help of a personalized nutrition plan, you’ll receive accurate biofeedback on what your body needs so that you can start reaching your goals faster and more efficiently than ever before with just a morning breath test.
This feedback can help you fine-tune your carb cycling plan, ensuring you are effectively alternating between fuel sources and promoting metabolic flexibility. By learning more about your body and its needs, you’ll quickly know whether you’re not eating enough carbs or eating too many on a given day. Having a high-carb day when your body isn’t ready for it can block fat burn.
Choose your carbs wisely
Not all carbs are created equal. When carb cycling, you’ll want prioritize complex carbohydrates that are rich in fiber and have a low glycemic index.
A carb "boost day" does not mean bingeing on cookies, cake, and crackers. It's important to fuel your body with nutritious carbs for the fiber, phytonutrients, and low-insulin response they provide.
These carbs digest more gradually than their simple counterparts, ensuring a consistent energy release rather than a rapid surge and subsequent slump.
Fiber helps you feel fuller after eating and is also important for keeping you regular, lowering cholesterol levels, stabilizing blood sugar levels, and helping aid in weight loss.
Simple carbs like candies, pastries, and white bread can cause rapid blood sugar spikes followed by crashes.
Synchronize with your menstrual cycle
It might be beneficial to align high-carb days with the luteal phase of the menstrual cycle when women often feel more fatigued and have increased calorie needs.
Focus on your other macros too
Even on low-carb days, ensure adequate protein and healthy fat intake. You can incorporate sources like lean meats, fish, avocados, and nuts.
Listen to your body
Every woman is unique. Track your feelings on different days, and adjust based on energy levels, mood, and hunger cues. This personalization will make carb cycling more effective and sustainable.
There are many promising benefits from carb cycling, however each individual responds differently to these types of dietary changes. Therefore what works for one person may not work for another. While there are many carb cycling plans out there, these generic plans are one-size-fits-all, and for best results, carb cycling should be tailored to the individual.
Using tools such as Lumen’s personalized nutrition can help to build a plan that is based on your specific body and its needs.
With daily nutrition recommendations, tracking and biofeedback, and habit-formation tools, you can learn how to fuel your body for optimal metabolic functioning.
Whether you have heard of carb cycling before or this concept is completely new to you, by now, you should be feeling more confident in your knowledge of carb cycling and its benefits.
While personalized carb cycling shows potential in addressing women-specific physiological considerations, it is crucial to understand that nutritional needs are highly individual.
What works well for one woman may not necessarily work for another. Therefore, it is recommended to learn about your body’s metabolic needs, follow a personalized nutritional plan based on your unique physiology. Remember to combine it with regular exercise and adequate hydration for best results.
You can start taking steps now to improve your metabolic function and overall health.
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Gower BA, Goss AM. A lower-carbohydrate, higher-fat diet reduces abdominal and intermuscular fat and increases insulin sensitivity in adults at risk of type 2 diabetes. J Nutr. 2015 Jan;145(1):177S-83S. doi: 10.3945/jn.114.195065. Epub 2014 Dec 3. PMID: 25527677; PMCID: PMC4264021.
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Marine is a registered dietitian with a passion for well-being, health and metabolism. She started her career as a clinical dietitian, opened her private practice to accompany patients from various backgrounds in their health journey, and is now providing nutrition support for Lumen’s customers.